Davidheiser S, Davies R E
Am J Physiol. 1982 Mar;242(3):R394-400. doi: 10.1152/ajpregu.1982.242.3.R394.
Phosphorylargnine utilization (delta PArg) was determined in isolated Limulus telson muscle during isometric and isovelocity contractions at long, intermediate, and short lengths when thick filaments were either long and staggered, long and aligned, or shortened. Muscles developed 30% of maximum force at a length of 0.5 Lo (Lo 7 micrometers sarcomere length) during isometric tetani of 5, 15, and 30 s; however, the rate of delta PArg was the same in both the 0.5 Lo and Lo groups. External force and delta PArg were both less during isometric tetani at lengths of 1.7 and 2.0 Lo compared with the values at Lo, as expected due to a reduction in thick-thin filament overlap. However, at lengths of 0.6 and 0.3 Lo delta PArg was the same as at Lo despite a decrease in external isometric tension. No significant delta PArg was measured when telson muscles shortened rapidly (0.8 Vmax) at long or short lengths indicating the thick filament shortening per se required little, if any, energy expenditure. The overall chemical efficiency of telson muscles for performing external work during slow isovelocity contractions was 31% in groups shortening equivalent distances (0.5 Lo) from starting lengths of 1.6 and 1.3 Lo and 15% in the group shortening from 1.1 Lo.
在等长和等速收缩过程中，当粗肌丝分别为长且交错排列、长且对齐或缩短时，在分离的鲎尾节肌中测定磷酸精氨酸利用率（ΔPArg）。在5秒、15秒和30秒的等长强直收缩期间，肌肉在长度为0.5 Lo（Lo = 7微米肌节长度）时产生的最大力为30%；然而，0.5 Lo组和Lo组的ΔPArg速率相同。与Lo时的值相比，在长度为1.7 Lo和2.0 Lo的等长强直收缩期间，外力和ΔPArg均较小，这是由于粗细肌丝重叠减少所致，正如预期的那样。然而，在长度为0.6 Lo和0.3 Lo时，尽管等长张力降低，但ΔPArg与Lo时相同。当尾节肌在长或短长度下快速缩短（0.8 Vmax）时，未测得显著的ΔPArg，这表明粗肌丝缩短本身几乎不需要能量消耗（如果有消耗的话）。在从1.6 Lo和1.3 Lo的起始长度缩短等效距离（0.5 Lo）的组中，鲎尾节肌在缓慢等速收缩期间进行外部功的总体化学效率为31%，而在从1.1 Lo缩短的组中为15%。
